<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8">
		<title>Document</title>		
		<style>
			* {
				padding: 0;
				margin: 0;
			}

			.nav {
				height: 90px;
				width: 100%;
				position: fixed;
			}

			.nav>* {
				position: absolute;
			}

			.nav>div {
				width: 100%;
				height: 100%;
				background-color: #3d3d3d;
				opacity: .1;
			}

			.nav>p {
				width: 100%;
				text-align: center;
				/*background-color: yellow;*/
				color: white;
			}

			.blue {
				width: 900px;
				height: 2000px;
				background-color: blue;
			}

		</style>
	</head>
	<body>

		<div class="nav">
			<div></div>
			<p>我们</p>
		</div>
		<div class="blue"></div>
		
	</body>
</html>